A number of signal transduction pathways have been implicated in behavioral, developmental and synaptic plasticity using pharmacological and genetic manipulations. Molecules identified as important in the generation of both short-term and long-term plasticity include CaMKII and PKA. The overlapping use of a few biochemical pathways to set up the circuitry for, and mediate, complex behaviors implies the existence of important temporal and/or spatial constraints on activity. This proposal is will use novel methods in Drosophila to detect and manipulate the spatial and temporal patterns of activation of protein kinases. Specific Aim #1 will probe the role of CaMKII autoregulation and localization in associative memory formation using temporally controlled expression of mutant kinase transgenes in cells known to be part of the memory circuit. Concurrent temporal and spatial control will be achieved by using either selectively inhibitable kinase transgenes or a tetracycline-controlled GAL4 enhancer trap strategy. The role of modulation of excitability as an important downstream consequence of CaMKII activation will be tested by manipulation of Eag potassium channel activity. Specific Aim #2 will identify the developmental window during which CaMKII acts to modify adult circuit formation. Once this window is established we will identify the sensitive cell groups. The morphological and gene expression consequences of early manipulation of CaMKII will be explored. Specific Aim #3 will develop and implement genetically based sensors to measure the activation of kinases in real time in intact behaving animals. The initial sensor will detect kinases such as PKA that activate gene expression via CREB and are also involved in short-term plasticity. These experiments will give us temporal and spatial information about the use of biochemical pathways during development and behavior. The high level of synteny in the biochemistry of neuronal function between mammals and flies leads to the expectation that these studies will have relevance for human learning disabilities.